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The database format notifyd is "private" to it. This makes it possible for smbcontrol and others to query notifyd's database with MSG_SMB_NOTIFY_GET_DB and inspect it without having to know exactly what format it uses. Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Jeremy Allison <jra@samba.org>
157 lines
5.2 KiB
C
157 lines
5.2 KiB
C
/*
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* Unix SMB/CIFS implementation.
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*
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* Copyright (C) Volker Lendecke 2014
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __NOTIFYD_NOTIFYD_H__
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#define __NOTIFYD_NOTIFYD_H__
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#include "includes.h"
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#include "librpc/gen_ndr/notify.h"
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#include "librpc/gen_ndr/messaging.h"
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#include "lib/dbwrap/dbwrap.h"
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#include "lib/dbwrap/dbwrap_rbt.h"
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#include "messages.h"
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#include "tdb.h"
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#include "util_tdb.h"
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/*
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* Filechangenotify based on asynchronous messages
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*
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* smbds talk to local notify daemons to inform them about paths they are
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* interested in. They also tell local notify daemons about changes they have
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* done to the file system. There's two message types from smbd to
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* notifyd. The first is used to inform notifyd about changes in notify
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* interest. These are only sent from smbd to notifyd if the SMB client issues
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* FileChangeNotify requests.
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*/
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/*
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* The notifyd implementation is designed to cope with multiple daemons taking
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* care of just a subset of smbds. The goal is to minimize the traffic between
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* the notify daemons. The idea behind this is a samba/ctdb cluster, but it
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* could also be used to spread the load of notifyd instances on a single
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* node, should this become a bottleneck. The following diagram illustrates
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* the setup. The numbers in the boxes are node:process ids.
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*
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* +-----------+ +-----------+
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* |notifyd 0:5|------------------|notifyd 1:6|
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* +-----------+ +-----------+
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* / | \ / \
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* / | \ / \
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* +--------+ | +--------+ +--------+ +--------+
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* |smbd 0:1| | |smbd 0:4| |smbd 1:7| |smbd 1:2|
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* +--------+ | +--------+ +--------+ +--------+
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* |
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* +---------+
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* |smbd 0:20|
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* +---------+
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*
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* Suppose 0:1 and 0:4 are interested in changes for /foo and 0:20 creates the
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* file /foo/bar, if everything fully connected, 0:20 would have to send two
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* local messages, one to 0:1 and one to 0:4. With the notifyd design, 0:20
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* only has to send one message, it lets notifyd 0:5 do the hard work to
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* multicast the change to 0:1 and 0:4.
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*
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* Now lets assume 1:7 on the other node creates /foo/baz. It tells its
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* notifyd 1:6 about this change. All 1:6 will know about is that its peer
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* notifyd 0:5 is interested in the change. Thus it forwards the event to 0:5,
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* which sees it as if it came from just another local event creator. 0:5 will
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* multicast the change to 0:1 and 0:4. To prevent notify loops, the message
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* from 1:6 to 0:5 will carry a "proxied" flag, so that 0:5 will only forward
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* the event to local clients.
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*/
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/*
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* Data that notifyd maintains per smbd notify instance
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*/
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struct notify_instance {
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struct timespec creation_time;
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uint32_t filter;
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uint32_t subdir_filter;
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void *private_data;
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};
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/* MSG_SMB_NOTIFY_REC_CHANGE payload */
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struct notify_rec_change_msg {
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struct notify_instance instance;
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char path[];
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};
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/*
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* The second message from smbd to notifyd is sent whenever an smbd makes a
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* file system change. It tells notifyd to inform all interested parties about
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* that change. This is the message that needs to be really fast in smbd
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* because it is called a lot.
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*/
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/* MSG_SMB_NOTIFY_TRIGGER payload */
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struct notify_trigger_msg {
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struct timespec when;
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uint32_t action;
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uint32_t filter;
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char path[];
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};
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/*
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* In response to a MSG_SMB_NOTIFY_TRIGGER message notifyd walks its database
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* and sends out the following message to all interested clients
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*/
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/* MSG_PVFS_NOTIFY payload */
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struct notify_event_msg {
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struct timespec when;
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void *private_data;
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uint32_t action;
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char path[];
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};
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struct sys_notify_context;
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typedef int (*sys_notify_watch_fn)(TALLOC_CTX *mem_ctx,
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struct sys_notify_context *ctx,
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const char *path,
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uint32_t *filter,
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uint32_t *subdir_filter,
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void (*callback)(struct sys_notify_context *ctx,
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void *private_data,
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struct notify_event *ev),
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void *private_data,
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void *handle_p);
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struct tevent_req *notifyd_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
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struct messaging_context *msg_ctx,
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struct ctdbd_connection *ctdbd_conn,
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sys_notify_watch_fn sys_notify_watch,
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struct sys_notify_context *sys_notify_ctx);
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int notifyd_recv(struct tevent_req *req);
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/*
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* Parse a database received via the MSG_SMB_NOTIFY_[GET_]DB messages to the
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* notify daemon
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*/
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int notifyd_parse_db(const uint8_t *buf, size_t buflen,
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uint64_t *log_index,
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bool (*fn)(const char *path,
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struct server_id server,
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const struct notify_instance *instance,
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void *private_data),
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void *private_data);
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#endif
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